大型稳态燃烧烟雾机燃烧模拟及尾气成分分析

Exhaust gas components of large-scale steady combustion fogger

为了提高大型稳态燃烧烟雾机的燃烧效果,减少CO、HC等有害气体产生,减少C颗粒的析出,提出了一种大型稳态燃烧烟雾机燃烧产物模拟的研究方法,用于大型稳态燃烧烟雾机的设计和改进。该方法将大型稳态燃烧烟雾机燃烧室简化为二维对称模型,采用Gambit软件建立几何形状及生成网格,用prePDF程序进行仿真计算,用FLUENT主程序湍流模型和非预混模型计算得出了燃烧产物的摩尔质量分数,用尾气检测仪对大型稳态燃烧烟雾机进行尾气化学成分测定试验研究,结果表明尾气成分HC、CO和NOX体积分数在燃烧室末端燃烧时受进气流量的影响均较大,但最终在排入大气前的喷管末端时各成分体积分数受进气流量的影响反而减小。这种数值模拟方法不仅可为燃料与空气配比及尾气生成提供分析方法,同时也为今后大型稳态燃烧烟雾机喷药口的热量混合及最佳雾粒的生成提供了基础。

For improving the combustion effect of the large-scale steady combustion fogger,reducing the emission of harmful gas of CO,hydroxide and so on,and decreasing the precipitation of the carbon particle,a method of simulating the combustion process and the distribution of the exhausted gases in a combustor was studied to improve the design of the large-scale steady combustion fogger.In the simulation,first,the combustor was simplified to a two-dimensional symmetrical model and the geometric shape of the combustor was established to generate the grid with the Gambit software.Then the combustion and generating process was simulated and calculated with the prePDF program.The mol mass fraction of the combusted product was calculated in the turbulence model and non-premix model of FLUENT.Finally,the chemical component of the exhausted gas was tested by the exhausted gas detector.The research is beneficial for the analysis of the ratio of fuel to air,the product of the exhausted gases,the heat mixture in the exhausted tube and the generation of optimum droplet.